The subject invention relates generally to the delivery of moisture to a dermatological surface, and, more particularly, to a composition for providing soluble medicaments and moisture to such surfaces when used either alone or in conjunction with a device.
The ability to provide a controlled, variable release of soluble medicaments or aqueous substances in a topical manner is desirable for treating a variety of diseases and ailments. For example, the general aging of the population is accompanied by a concomitant increase in the number of cases of dry mouth, also referred to as xerostomia. This is a condition in which salivary flow is either decreased or undergoes a compositional change. Not only is this affliction irritating, it can also aggravate problems involving swallowing and speaking and may even lead to increased tooth decay. In the elderly xerostomia is particular dangerous since it may interfere with eating and result in malnutrition.
Such a salivary alteration can occur as a natural glandular disfunction, as the result of any of a number of illnesses including rheumatoid arthritis, Lupus, diabetes, HIV and Sjxc3x6grens syndrome, as a side effect of radiation or chemotherapy treatments for other illnesses, through ingestion of over-the-counter and prescription drugs or may even arise out of psychological conditions such as stress and depression. Since dry mouth may be either a temporary or a permanent condition, the importance of finding an inexpensive, simple method for providing relief from its symptoms is especially great.
The prior art has focused on either osmolar exchange of medicaments or on the imbibement of a saliva substitute or water for the dissolution of subsequently delivered medications. Research into this area has focused mainly on developing improved durability of compositions inserted directly into the mouth. An integrated approach for providing medication or water in the mouth through a controlled release delivery system incorporating a gel and/or polymer into a mechanical device has been underemphasized in the art.
Numerous issues must be addressed in developing such an integrated delivery system. First, the delivery system must be biocompatible since it is designed for use in the oral cavity. Second, the system must be pleasant and easy to use as it will be distributed to the general public. It should not be accompanied by any chemical or repellent taste or smell. Third, it must achieve a comfortable fit inside the user""s mouth. This point is particularly important since, due to dryness, the mouth may be prone to infection and is likely to be highly sensitive. A fourth consideration is safety. The system must exhibit resistance to microbial growth and, since it will be in use primarily at night, must not present a choking or swallowing risk to the user while asleep. Finally, such a system would have to exhibit physical stability and durability along with the capability to release a known amount of fluid into a patient""s mouth at a controlled, but variable, rate for a prolonged and predictable period of time.
It is known to have syringe applicators or encapsulated sponges for delivering medicaments or moisture. However, compositions used for the purpose of topical delivery of medicament do not typically exhibit any hydrodynamic properties which would enhance their delivery capability. Furthermore, such compositions cannot provide the dual function of both delivering fluids to and removing them from a chosen site as desired.
One of the dangers of directly inserting a composition into the mouth for the purpose of treating xerostomia is the possibility that the composition will partially degrade or disintegrate during the night or that the user will bite off part of the composition and swallow it. Thus, a serious risk of choking is often presented. On the other hand, when insertion of a device into the mouth is used to treat xerostomia, different kinds of problems are presented: discomfort and damage to tissue areas coming into contact with the device through abrasion or cutting.
What is missing from the prior art is a dual-purpose delivery system for medicaments and moisture including a composition which is viscoelastic and functions as a hydrodynamic pump, easily releasing fluid in a variably controlled manner, and which may be used not only to deliver fluids to a desired site but, if desired, to remove them as well. In addition, such a delivery system must successfully address the issues described above.
The present invention relates to a hydrogel composition for hydrating and dehydrating dermatological surfaces and to a device for use in conjunction with the composition for delivering moisture and, if desired, medication to a user""s mouth in treating xerostomia.
The hydrogel composition is comprised of two polymerizable materials, a polymerization catalyst and a two-part polymerization medium. The polymerizable materials are a hydrophilic acrylate-based monomer and a crosslinking agent. In the preferred embodiment, the polymerizable materials are 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate, respectively. The polymerization catalyst is a redox initiator system. In the preferred embodiment, a two-part redox catalyst system is used comprised of ammonium persulfate and tetramethyl-ethylene diamine. The polymerization medium is comprised of distilled water and a low molecular weight aliphatic alcohol such as isopropyl alcohol. A hydrodynamic hydrogel composition is formed from a combination of these materials which, after hydration, can release consistent amounts of moisture over a relatively long period of time onto a surface with which it is placed in contact. Alternatively, after dehyration, the composition can absorb moisture from a surface with which it is placed in contact.
A method for forming the hydrogel composition is also provided in which specified percentages by weight of all of the ingredients are mixed to achieve the desired composition. First, the two polymerizable-materials are mixed with the polymerization medium. Then, the ammonium persulfate is added to the preexisting mixture. Only after the ammonium persulfate is thoroughly dissolved may the tetramethyl-ethylene diamine be introduced to the mixture. The resultant composition must be transferred within two to three minutes to a desired mold. The molded composition sets up within between twenty and twenty-five minutes after which it may be removed from the mold and washed to remove the residual monomer from the molded composition.
The device is molded from a thermoplastic material and shaped so as to generally conform to the contours of the interior of a user""s mouth. The device is comprised of a center section to each end of which is attached a reservoir section. Each reservoir section has a generally xe2x80x9cIxe2x80x9d beam shape in which the top and bottom members of the xe2x80x9cIxe2x80x9d beam generally curve towards each other. A fluid permeable cavity is included in the center support of the xe2x80x9cIxe2x80x9d beam for receiving and storing medications, fluid and/or flavoring. The center section and each of the reservoir sections include ribbed segments to provide additional flexibility to the device and enable it to further conform to the contours of a user""s mouth. In the center section and both of the reservoir sections, small portions of the thermoplastic material are removed to leave holes through the material. When the hydrogel composition is allowed to mold to the device, the holes formed within the thermoplastic material enables the composition to form a strong mechanical bond to the device while the curvature of the top and bottom members helps to more securely retain the composition in contact with the device. The fluid permeable nature of the cavity permits its contents to be delivered and dispersed over time throughout the composition and, hence, onto surfaces with which the composition is placed in contact.
A primary objective of this invention is to provide a hydrogel composition capable of hydrating or dehydrating a surface with which it is placed in contact.
An additional objective of this invention is to provide a hydrogel composition comprised of two polymerizable materials, a polymerization catalyst and a polymerization medium.
It is a further objective of this invention to provide a hydrogel composition based on use of a hydrophilic acrylate-based monomer, a crosslinking agent, a redox catalyst system, a low molecular weight aliphatic alcohol and distilled water.
Yet another objective of this invention is to provide a composition for use as a wound dressing which can either finction to absorb fluids from a wound when used in a dessicated state or to hydrate wounds when applied thereto.
Still a further objective of this invention is to provide a composition for use in implanted hormone or other types of therapy wherein the composition could release medical materials over a prolonged period of time at a controlled rate.
Another objective of this invention is to provide a composition useful in field chemical sampling where it could absorb chemicals in the field and later release in a laboratory.
An additional objective of this invention is to provide a composition for managing dry eyes by hydrating areas around or in contact with the eye.
It is still another objective of this invention to provide a method for making a polymerized hydrogel composition capable of hydrating or dehydrating a surface with which it is placed in contact wherein distilled water, a low molecular weight aliphatic alcohol and two polymerizable materials are mixed together and the first part of a two part redox catalyst system is thoroughly dissolved in the resulting mixture before the second part of the two part redox catalyst system is added to the mixture.
A still further objective of this invention is to provide a composition in which both the moisture release rate and the moisture absorption rate are controllably variable.
Yet an additional objective of this invention is to provide a method for controllably varying the moisture release and the moisture absorption rates of a composition used in hydrating and dehydrating a surface.
It is yet a further objective of this invention to provide a device for use with a composition in treating xerostomia in which the device is molded from a thermoplastic material and is comprised of a center section connected on each end thereof to a reservoir section.
Another objective of this invention is to provide an applicator for treatment of xerostomia comprised of a hydrogel composition and a device onto and through which the hydrogel composition is mechanically bonded wherein the applicator fits comfortably within a user""s mouth.
Still another objective of this invention is to provide an applicator for treatment of xerostomia comprised of a hydrogel composition and a device to which the hydrogel composition is bonded wherein the device includes a fluid permeable storage compartment formed therein for delivering medication, fluid and/or flavoring to the composition.